Machine parts can, for example, be reliably connected to one another such that they are pressed against one another with a high contact pressure in the region of the contact surfaces provided for this purpose. The contact pressure can be produced, for example, using bolts, screws, or similar connecting means, which clamp the machine parts against one another in a direction transverse, in particular perpendicular, to the contact surfaces. As long as the frictional force resulting from the friction between the contact surfaces is not overcome, the bond made of the machine parts is mechanically stable, i.e. there is no relative movement between the machine parts. The same applies with regard to the frictional torque.
The amount of the frictional force depends on the contact pressure and on the coefficient of friction of the contact surfaces. A critical situation can occur if the load acting on the bond is so high that the maximum frictional force that can oppose the loading force is overcome. In such a situation, the connecting means, which are primarily designed for a tensile load, are loaded to the point of shearing and can fail, or the bond can be destroyed by internal movements. The bond should therefore be designed such that the available frictional force is not exceeded by dislocating forces during the anticipated operating conditions.
A high frictional force can be achieved by a high contact pressure and a high coefficient of friction. Within certain limits, the production of a high frictional force by a correspondingly high contact pressure is still relatively easy. At very high contact pressures, however, ever higher demands are placed on the tensile load-bearing capacity of the connecting means and also on the pressure load-bearing capacity of the machine parts to be connected, which can be increasingly difficult to meet, or can be met only with unreasonable expenditures. It is therefore desirable, in particular in applications wherein the bond is subjected to high loads, to achieve as high as possible a coefficient of friction. This is for example the case with the fixing of bearings, in particular of rotor bearings, of wind turbines. There it can be required or desirable to achieve as high as possible a frictional torque between an inner ring or an outer ring of the bearing, for example of a double row tapered roller bearing, and an associated attachment flange. The same applies to a bearing having a plurality of inner rings. In such a case, a relative movement between the inner rings should be prevented.